Systemic Inflammation Markers Show Promise in Predicting Outcomes Across Diverse Infections
ISTANBUL – Emerging research highlights the potential of readily available blood markers-Neutrophil-to-Lymphocyte Ratio (NLR), Prognostic Nutritional Index (PNI), and Systemic Inflammation Index (SII)-to predict disease severity and mortality across a surprisingly broad spectrum of infectious diseases, from pneumonia to endocarditis. A growing body of evidence suggests these simple, inexpensive tests could offer clinicians valuable insights for risk stratification and improved patient management.
While traditionally used in oncology, recent studies demonstrate the diagnostic and prognostic utility of NLR, PNI, and SII in bacterial and viral infections. These indexes reflect the body’s inflammatory response, offering a snapshot of immune function and perhaps signaling the likelihood of adverse outcomes. The findings, published across journals including Med Res J, Arch Curr Med Res, and J Saudi Heart Assoc between 2017 and 2023, underscore a shift toward leveraging systemic inflammation as a key indicator of patient prognosis.
Several studies have investigated the role of these indexes in respiratory infections. Research published in Med Res J (2023) found a correlation between SII and both inflammation index and pneumonia severity. similarly, a 2022 study in Arch Curr Med Res indicated a predictive role for NLR, SII, and PLR in COVID-19 mortality.
Beyond respiratory illnesses, the indexes are showing promise in other infectious contexts. Researchers found diagnostic value of SII in neonatal urinary tract infections (Am J Perinatol, 2022) and its relevance in diabetic foot infections (Int J low Extrem Wounds, 2022). In infants, SII was found to predict serious infections (Postgrad Med, 2022).
infective endocarditis, a serious heart infection, has also been the focus of examination. A 2020 study in J Saudi Heart Assoc demonstrated that SII predicts mortality in patients with this condition, and a 2022 study in Int Heart J linked SII to embolic events-a risky complication-in endocarditis patients. Existing scoring systems for predicting mortality after infective endocarditis surgery, such as those developed by Gatti et al.(J Am Heart Assoc, 2017), Di Mauro et al. (Int J Cardiol, 2017), and De Feo et al.(Sci World J, 2012), may benefit from the incorporation of these inflammatory markers.
The ease of calculation and low cost of NLR, PNI, and SII make them potentially valuable tools for widespread clinical use, particularly in resource-limited settings. Further research is needed to validate these findings in larger,multi-center studies and to determine the optimal cut-off values for each index in different patient populations. Though, the accumulating evidence suggests these simple blood tests could soon become integral to assessing and managing infectious disease risk.
